This question already has an answer here:
- How to pivot a dataframe 1 answer
I have a dataframe (df) that looks like this:
+---------+-------+------------+----------+
| subject | pills | date | strength |
+---------+-------+------------+----------+
| 1 | 4 | 10/10/2012 | 250 |
| 1 | 4 | 10/11/2012 | 250 |
| 1 | 2 | 10/12/2012 | 500 |
| 2 | 1 | 1/6/2014 | 1000 |
| 2 | 1 | 1/7/2014 | 250 |
| 2 | 1 | 1/7/2014 | 500 |
| 2 | 3 | 1/8/2014 | 250 |
+---------+-------+------------+----------+
When I use reshape in R, I get what I want:
reshape(df, idvar = c("subject","date"), timevar = 'strength', direction = "wide")
+---------+------------+--------------+--------------+---------------+
| subject | date | strength.250 | strength.500 | strength.1000 |
+---------+------------+--------------+--------------+---------------+
| 1 | 10/10/2012 | 4 | NA | NA |
| 1 | 10/11/2012 | 4 | NA | NA |
| 1 | 10/12/2012 | NA | 2 | NA |
| 2 | 1/6/2014 | NA | NA | 1 |
| 2 | 1/7/2014 | 1 | 1 | NA |
| 2 | 1/8/2014 | 3 | NA | NA |
+---------+------------+--------------+--------------+---------------+
Using pandas:
df.pivot_table(df, index=['subject','date'],columns='strength')
+---------+------------+-------+----+-----+
| | | pills |
+---------+------------+-------+----+-----+
| | strength | 250 | 500| 1000|
+---------+------------+-------+----+-----+
| subject | date | | | |
+---------+------------+-------+----+-----+
| 1 | 10/10/2012 | 4 | NA | NA |
| | 10/11/2012 | 4 | NA | NA |
| | 10/12/2012 | NA | 2 | NA |
+---------+------------+-------+----+-----+
| 2 | 1/6/2014 | NA | NA | 1 |
| | 1/7/2014 | 1 | 1 | NA |
| | 1/8/2014 | 3 | NA | NA |
+---------+------------+-------+----+-----+
How do I get exactly the same output as in R with pandas? I only want 1 header.